The present invention relates to the device taught in application Ser. No. 07/046,722, which is capable of both inputting X, Y coordinates of a light emitting or absorbing stylus into a computer and scanning or digitizing graphic information on a planar surface such as paper. As in application Ser. No. 07/046,722 the design is such that one or more photodetectors used to determine the Cartesian coordinates of the stylus are capable of digitizing graphic information contained on sheet material such as paper.